The invention relates to a method of therapy for treating cows effected by subclinical or clinical mastitis and the subsequent nutritional maintenance of the cows to control, or minimize, reoccurrence of mastitis and to a composition useful therein.
Mastitis is the most underestimated single disease that effects dairy cattle. This profit stealer is so insidious and unspectacular that even dairymen working with it daily fail to understand its full importance.
Mastitis is the inflammation of the mammary gland regardless of the cause. The disease is characterized by the presence of a significantly increased leukocyte content in the milk from effected glands.
The definition of mastitis arrived at by the International Dairy Confederation requires the finding of pathogenic microorganisms in the milk and also a concentration of somatic cells in excess of 500,000/ml. This combination of criteria protects against misdiagnosis arising from contamination of the milk with bacteria from the external environment. This combination of criteria also permits one to distinguish between a pathogen population actually established in the gland and one that is merely harbored in the streak canal.
The simplest method for detecting mammary inflammation has been the indirect estimation of leukocytic infiltration of the gland by one or another of the so called screening tests. The California Mastitis Test (CMT) and the Kendall Mastitis Test (KMT) are methods of choice in the field.
The value of the screening tests may better be appreciated when one considers that the clinical syndrome may vary from a preacute inflammation, with toxemia, to a fibrosis which develops so gradually that it may escape observation until most of the secretory tissue has been destroyed. There is, of course, the additional danger that the bacterial contamination of milk from affected cows may render it unsuitable for human consumption or interfere with manufacturing processes and in rare cases even provide a mechanism which would spread disease to humans. Tuberculosis, streptococcal sore throat and brucellosis may be spread in this way.
In most countries, surveys of the incidence of mastitis, irrespective of cause, show comparable figures of about 40% morbidity amongst cows and a quarter incidence of about 25%. Most estimates show that on the average an affected quarter suffers a 30% reduction in productivity. An affected cow is estimated to lose 15%, or more, of its production.
While it is recognized that to prevent new intramammary infections, good sanitation continues to be of primary importance, to achieve good sanitation, several factors should be given special consideration. Factors such as nutrition, climate, and stress probably influence new infection rates, but there is insufficient evidence at this time to assess their influence.
Mastitis control should be based on preventing new infections in cows during lactation and eliminating infections in the nonlactation period. In devising a practical control program is necessary to concentrate on those factors which will substantially reduce the new infection rate.
In cases of chronic clinical mastitis, it must be taken into consideration that treatment is generally done by dairymen using over-the-counter products. This is not to say that veterinarians should not be consulted by dairymen with respect to overall management of their mastitis control program.
For economic reasons, the success of a control program is measured not only by the extent of the decrease in the level of infection but also by how quickly this is achieved. If a control program is to reduce levels of infection appreciably within a reasonable time, methods used must deal with all infections, not just those new infections in lactating cows, which may only comprise 50% of the total number of infections.
At the present time the principal means of decreasing the level of infection is through use of antibiotics. As a practical matter due to the fact that antibiotics are often times rather specific in their action, the dairymen must of necessity generally rely upon the services of a veterinarian, with associated appropriate laboratory facilities for identification of causative organisms.
As is well recognized by knowledgeable scientists a list of microorganisms associated with bovine mastitis is quite extensive both with regard to genus and species.
Mastitis research workers approximate that 90 to 95% of all cases of mastitis are caused by four species of bacterial cocci, i.e., Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae, and Streptococcus uberis. The 90 to 95% figure refers, generally, to results of herd survey studies where organisms causing subclinical mastitis predominate.
The next most important group of pathogens are the bacilli, including Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Corynebacterium pyogenes. Occasional outbreaks have been reported for lesserknown organisms such as actinomycetes, fungi, yeasts, mycoplasma, rickettsia, viruses, and algae. Infections with these organisms tend to be of shorter duration than for the cocci, and the incidence of clinical disease is significantly higher.
Thus the wide variety of pathogens responsible for mastitis, and differences in epidemiologic patterns, compound the problem of preventing, treating and controlling the disease.
Individual cases of mastitis vary widely in severity and duration, but for purposes of convenience each case may be defined as clinical or subclinical.
Clinical mastitis is accompanied by obvious changes in the appearance of the milk and the affected quarter. Milk may include flakes or clots and the quarter may be hot, swollen, and sensitive.
Subclinical mastitis results in changes in the milk and secretory tissue of the udder that cannot be observed visually and can be detected only with a sensitive screening test or by culturing those samples in a laboratory to determine the presence of mastitis organisms. Subclinical mastitis is estimated to be present in about 50% of all dairy cows in an average of two quarters each. This form is 15 to 40 times more common than the clinical form and most clinical cases are preceded by subclinical cases.
As indicated, at the present time, the principal means for increasing the rate of elimination of infections is by using antibiotics to treat clinical and subclinical mastitis together with similar therapy of nonlactating cows in a control program that also includes good milking machine management and a hygiene routine that includes both premilking and postmilking teat disinfection.
In this latter regard numerous U.S. patents propose compositions for external application to the udder and teats of cows to aid in the prevention of mastitis. Representative of such patents are U.S. Pat. Nos. 3,728,449; 3,950,554; 3,993,777; and 4,012,504. It is believed that the compositions proposed in these patents are such that rely upon the known topical microbicidal action of iodine, and inorganic iodide or an indophor as the biologically active constituent of the composition.
However, there is an increasing awareness that measures such as teat dipping and therapy of nonlactating cows are not effective against coliform organisms, by far the most important environmental pathogens. Further, most microorganisms have demonstrated an uncanny ability to develop tolerance to antibiotics. It is axiomatic that the development of new antimicrobial agents should thus be encouraged.
Despite the accumulated knowledge about bovine mastitis, too few of the persons concerned with milk production are fully aware of the economic advantages of mastitis reduction techniques.
The economic advantage, or impact, of mastitis can better be appreciated when it is realized that of over an estimated two hundred million dairy cows world wide, 35 to 40% are estimated to be affected by mastitis. Losses in 1976 due to bovine mastitis, according to U.S.D.A., has been estimated to exceed one billion dollars in the U.S. alone, and this represents the effect of mastitis on only 5% of the world dairy population. While world figures are sketchy, projections from the U.S.D.A. figures reveal a world wide loss figure exceeding twenty billion dollars annually. Thus, if mastitis could be contained, i.e., at a level of less than about 5% infection on U.S. dairy farms, the net profit from dairying could be tripled.
For an in depth consideration of the economic problems of mastitis, reference is made to the paper entitled Mastitis Losses, authored by Charles N. Dobbins, Jr., DVM, Journal of the American Veterinary Medical Association, volume 170, no. 10, May 15, 1977, pages 1129-1132. In a direct quote from page 1129 of the paper the author states "The tragedy of mastitis losses is that the average diaryman usually does not recognize the 2 major losses (production loss and replacement cost). If you ask a dairyman what his mastitis losses are, he will generally refer to veterinary fees, drug costs, and discarded milk, since he pays for these out of his pocket. These losses, however, are relatively insignificant when compared with production loss and increased replacement cost."
Thus, the main object of the present invention is to reduce economic losses caused by intramammary infection.
It is another object of the present invention to provide a composition and method for the treatment and control of bovine mastitis.
It is a further object of the present invention to provide a non-antibiotic composition and method of utilizing the same which can be safely and economically utilized by dairymen to effectively treat and control bovine mastitis.
It is still another object of the present invention to provide such a composition that may be administered orally or parenterally.